Stent for heart valve

ABSTRACT

A heart valve stent that includes an annular framework, preferably of bendable material, having three rounded apexes interconnected by support arms curved to incline away from the apexes. Additional support arms are included parallel to and axially beyond the first support arms. For use in the mitral position, the framework is circumscribed by an outer ring, which receives an annular element of felt or other suitable material. The heart valve is positioned on the stent, with its marginal portions overlapping it and affixed to it by sutures.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to a supporting framework, or stent, for anatural or synthetic heart valve.

The prior art

At the present time, surgical techniques allow the transplanting ofaortic valves in the hearts of human patients, where they are located ineither the aortic or mitral position. In such an operation, a naturalvalve from an animal or human, or alternatively a synthetic valve, isimplanted in the heart. There exists, however, the need for an improvedmeans for securing and supporting the valve in the heart to assure itsproper functioning and to avoid clotting or other difficulties. Inaddition, there has been lacking a suitable means for preparing naturalheart valves in advance for implantation so that they may be storeduntil the requirement for use arises.

SUMMARY OF THE INVENTION

The present invention provides a stent for natural or synthetic heartvalves that results in an improved means for supporting and grafting theheart valve in the patient. This invention makes possible thepreparation of natural heart valves, such as those from animals or fromhumans, which are applied to the stents under controlled conditions andmay be stored suitably so that an adequate supply of the heart valvesmay be maintained.

The stent is usable for valves to be used in both the aortic and mitralpositions. It comprises a frame of generally tubular configuration thatincludes three arcuate apexes interconnected by support arms. The apexesare positioned at the approximate locations of the aortic commissures.By having an arcuate contour, they have a finite dimension in adirection circumferential of the stent, so that dimension variations inthe valves may be accommodated. Upper and lower support armsinterconnect the apexes, being scalloped to extend downwardlyintermediate the apexes. Both serve as a means for securing theperimeter of the valve cusps to the stent by suturing or otherappropriate means. Preferably, the stent is of deflectable material,such as stainless steel having some malleability, so that the uppersupport arms may be bent upwardly. By virtus of their scalloped shape,this increases the spacing of the arms from the central axis of thestent, so that the stent may be increased in width to fit individualvalves of different configurations. The scalloped shape of the upperarms also allows placement of the valve in the aortic position withoutobstructing the coronary ostia.

When the stent is used for valves that are to be installed in the mitralposition, it may be provided with a ring outwardly of the lower supportarms. This ring provides a means for affixing the stent to the heart. Afelt ring is secured to the stent at the location of the attaching ring,providing a hemodynamic seal and a suitable bed over which tissue can beattached. The mitral leaflet and endocardium are brought over the atrialaspect of the attaching ring and affixed to the felt ring.

Thus, as either version of the stent is used, there is no exposure ofmetal to the portions of the heart where clotting is a problem, and withonly tissue exposed to the blood in the critical areas tendencies towardclotting are minimized.

An object of this invention is to provide an improved stent for naturalor synthetic heart valves.

Another object of this invention is to provide a heart valve stent thatcan accommodate valves of different dimensions.

A further object of this invention is to provide an arrangement by whicha heart valve is supported on a stent and secured so that only tissue orother material that does not promote the formation of clots will beexposed in critical areas of the heart when clotting might occur.

An additional object of this invention is to provide a stent thatpermits advance preparation under controlled conditions of heart valveswhich may be stored under suitable conditions until required.

A still further object of this invention is to provide a stent contouredto accommodate animal heart valves for use in xenografts.

These and other objects will become apparent from the following detaileddescription taken in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of the stent of this invention constructedfor use in the aortic position;

FIG. 2 is an enlarged fragmentary sectional view taken along line 2--2of FIG. 1, illustrating the rounded cross-sectional contour of theelements of the stent;

FIG. 3 is a perspective view, partialy broken away, showing the stent ofFIG. 1 with an aortic valve affixed thereto;

FIG. 4 is a side elevational view of the stent, showing how the supportarms may be deflected for increasing the transverse dimension;

FIG. 5 is a perspective view of the stent constructed for use in themitral position;

FIG. 6 is a perspective view, partially broken away, of an assembly ofthe stent of FIG. 5 and a heart valve;

FIG. 7 is a perspective view, partially broken away, illustrating amodified attachment of the heart valve to the stent;

FIG. 8 is an enlarged sectional view taken along line 8--8 of FIG. 7;

FIG. 9 is a sectional view similar to FIG. 8 with the addition of a ringaround the outer perimeter of the assembly;

FIG. 10 is a view similar to FIG. 9, but in which a cloth member hasbeen applied over the stent prior to attachment of the heart valve;

FIG. 11 is a perspective view, partially broken away, of a heart valveassembly for use in the mitral position in which a cloth covering isprovided over certain marginal portions;

FIG. 12 is a perspective view of a heart valve for use in the mitralposition in which there is a cloth attaching ring instead of a metalring; and

FIG. 13 is an enlarged sectional view taken along line 13--13 of FIG.12.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The stent 10, shown in FIGS. 1, 2 and 3, is for use in the aortic orpulmonary location. It constitutes an annular framework, circular inplan, that may be constructed of noncorrosive metal, such as stainlesssteel, or of plastic. When made of metal, it should have somemalleability which permits the device to be deflected to alter its shapeslightly from that illustrated. This has the advantage of allowing it toaccommodate valves of different dimensions, as will be explained below.Preferably, the metal stent is produced from a single piece of material.This avoids any welded, brazed or other connections, eliminating thelikelihood of galvanic corrosion after it has been implanted. Allportions of the stent are rounded at their edges so that no sharpcorners are presented (see FIG. 2).

The stent 10 includes three apical portions 11, 12 and 13, which are ofgenerally oval shape including rounded upper portions. The central areas14, 15 and 16 of the apical portions 11, 12 and 13 are cut away.Particularly when the stent is intended for use with animal valves, theapical portions are not distributed evenly around the perimeter of thestent 10. There is an equal angular spacing between the apical portions11 and 12, and between the apical portions 12 and 13. However, thespacing between the apical portions 11 and 13 is less than that betweenthe other two adjoining apexes. Usually, the spacing between the apexes11 and 13 is within the range of approximately 17% to 33% under thespacing of the other apexes, preferably around 20% to 25% less. This isin order that the stent will conform to the spacing of the commissuresof the valve to be applied to it, which, for animals, is very close tothis proportioning.

Interconnecting the lower sides of the apical portions 11, 12 and 13 areupper support bars 18, 19 and 20. These are scalloped, being curved awayfrom the apical portions 11, 12 and 13 so that they are concave towardthe end of the stent where the apical parts are located.

Beneath the apexes 11, 12 and 13, as the device is illustrated, areshort depending posts 22, 23 and 24 which extend parallel to the axis ofthe stent 10. To these posts are attached lower support arms 25, 26 and27. The latter elements are shaped generally the same as the uppersupport arms 18, 19 and 20 and are spaced an equivalent distance fromthe stent axis. Again, therefore, the lower support arms are ofscalloped configuration, being inclined downwardly intermediate thesupport posts. However, the lower support arms 25, 26 and 27 are notscalloped as deeply as are the upper arms.

As shown in FIG. 3, an animal aortic valve 28 is associated with thestent 10 for use in a xenograft. The valve 28 is secured to the stent byappropriate means, such as sutures 29. The valve commissures arepositioned at the apexes, while the margins of the cusps conform to thescalloped configuration of the support arms. The marginal portions 30and 31 of the valve cusps are extended over the support arms of thestent and overlap them, being doubled over the stent where theattachments are made. Consequently, the stent 10 is covered after thevalve 28 is affixed.

The presence of the various apexes and support arms assures that thereis a portion of the stent conforming to the shape of the valve 28 thatis available for secure attachment of all peripheral parts of the valve.The arcuate upper portions of the apexes 11, 12 and 13 allow latitude inpositioning of the commissures of the valve. There are some dimensionaldifferences among all natural valves, and the spacing of the commissuresmay vary to some degree. With the upper portions of the apexes 11, 12and 13 being arcuate, valves of different proportions may beaccommodated and allowed to assume their natural contour while stillbeing afforded ready and appropriate locations for attachment. In otherwords, if the spacing of the commissures does not correspond exactly tothe distances between the centers of the apexes, the commissuresnevertheless may be affixed to side portions of the apexes and therebysupported properly and in conformance with the natural valve contour.

Another advantage lies in the scalloped configuration and deflectablecharacteristics of the upper support arms 18, 19 and 20. By bending thesupport arm upwardly, as indicated in phantom in FIG. 4, the spacing ofthe arm from the central axis of the stent 10 becomes increased.Therefore, for valves of larger dimensions or those of irregularproportions, the arms may be deflected as required to assure that thestent provides the precise fit needed for the valve. Accordingly, thestent may be given an exact configuration to conform to the individualvalve being assoicated with it. The upper arms 18, 19 and 20 arescalloped more deeply than are the lower support arms to provide for amaximum amount of dimensional variation upon deflection of the upperarms.

This advantage is realized with stents of metal construction in whichthe upper support arms may be deflected. This does not hold true,however, for stents made of plastic, as suitable plastics cannot be bentto assume different shapes permanently. The scalloped configuration ofthe upper support arms not only makes dimensional changes possible, butalso allows placement of the valve in the aortic position withoutobstructing the coronary ostia.

The stent 32 shown in FIG. 5, for mitral or tricuspid location, has thesame general configuration as the aortic stent, but is of larger andslightly heavier construction. Additionally, it includes an outer ring,which is used in securing the stent to the heart.

The stent 32, as illustrated, includes rounded apexes 33, 34 and 35,each being cut away interiorly so as to be of annular and generally ovalconfiguration. Downwardly scalloped upper support arms 36, 37 and 38interconnect the apexes. Beneath the upper arms are similarly shaped butmore shallowly scalloped lower support arms 40, 41 and 42. These connectat their ends to posts 43, 44 and 45 that extend below the apexes 33, 34and 35, respectively.

Additional short posts 46, 47 and 48 extend downwardly, as the device isshown, from the junctures between the adjacent lower support arms 40, 41and 42. At their upper ends, the posts 46, 47 and 48 are generallyparallel to the axis. The bottom portions of the posts 46, 47 and 48,however, are bent substantially at right angles to extend generallyradially to an outer attaching ring 50. The latter element is circularand of greater diameter than the annulus defined by the support arms.

The attachment of the valve 51 to the stent 32 for the mitral positionis essentially the same as that of the valve 28 to the aortic stent 10.Again, suturing 52 normally is employed to effect the attachment of themarginal portions of the valve 51. In addition, however, an annularmember 53 of felt or other suitable material is positioned around thestent 32 between the outer ring 50 and the annular structure provided bythe posts 46, 47 and 48 and the lower arms 40, 41 and 42. The felt ring53 provides a hemodynamic seal and a suitable bed over which tissue canbe affixed. The mitral leaflet and the endocardium 54 are brought overthe atrial aspect of the outer ring 50 (i.e., the end remote from theapexes) and affixed by sutures to the felt ring 53. This serves animportant function in the prevention of blood clots. The ring 50 andother parts of the stent 32 are completely covered in the portions ofthe assembly that are positioned in localities of the heart whereclotting is likely to take place. Therefore, in the critical zones ofthe heart where a thrombus may occur, any exposure of material thatmight promote clotting is minimized. The ring 50 provides a stable andsecure means for affixing the stent and associated mitral valve to theheart. This is accomplished normally by sutures to attach the valve inthe mitral position between the left atrium and ventricle.

Various modifications may be made in the manner in which the heart valveis mounted on the stent. For example, as shown in FIGS. 7 and 8, theheart valve 55 attached to the aortic stent 10 is not doubled over theupper perimeter of the stent. In other words, the upper margin of theheart valve is not arranged as illustrated in FIG. 3, where the margin31 is shown doubled over the upper arms 18, 19 and 20 and the apexes 11,12 and 13. Instead, the margin 56 of the heart valve 55 of FIGS. 7 and 8is allowed to project beyond the stent to provide a free edge portion oftissue. Inwardly of this, sutures 57 secure the upper part of the heartvalve to the stent. The marginal edge portion 56 provides a flap ofmaterial which may be used in attaching the heart valve 55 to the heartwall. This technique is preferred in some instances.

The arrangement of FIG. 9 is similar to that of FIG. 8 except that aring has been added around the perimeter of the stent. This is anannular member, normally of a suitable cloth such as felt, or of sponge,held in place by sutures and extending around the exterior of thesupport arms below the apexes of the stent. This ring provides asuitable bed for fibrous ingrowth after the grafting of the valve in theheart. This also provides a compliant member capable of conforming to anirregular aortic root to assure a snug fit and a hemodynamic seal.Moreover, the annulus of the valve supported on the stent often isirregular, further adding to the desirability of the exteriorly appliedmember in such instances.

While illustrated in FIG. 9 in conjunction with an attachment of theheart valve to leave a free marginal flap 56, the ring 58 also isapplicable when the heart valve is attached upon a doubling over of thetissue as indicated in FIG. 3. The ring 58 may be used on either thestent 10 for the aortic position or the stent 32 for the mitralposition.

FIG. 10 illustrates a further modification in which an annular clothelement 60 is provided on the stent prior to attachment of the heartvalve. The cloth 60 is, in effect, tubular in shape, providing a sleevethat has a continuous transverse wall which overlaps and receives theupper and lower arms of the stent. However, the annular cloth member 60does not extend over the stent apexes. Normally, a ring 58 will beutilized in conjunction with an assembly that embodies the annular clothelement 60. This cloth covering of the inner and outer stent surfaces,which can be applied to either the aortic or the mitral stent, providesa means by which the tissue is more easily attached to the stent. Itresults also in a matrix for ingrowth and subsequent fixation of thedonor valve by the host tissue.

In FIG. 11, there is illustrated a heart valve 51 on the stent 32 foruse in the mitral position similar to the arrangement of FIG. 6 but witha cloth layer 62 added over the periphery of the stent and inwardly ofthe outer ring 50. The layer of cloth 62 follows the contour of thestent and is fixed in place by sutures. The cloth layer 62 adds a matrixfor fibrous ingrowth, facilitating the binding of the host tissue to thegraft tissue. It also covers the sutures and the ragged edges of themargins of the heart valve that overlap the framework of the stent,providing an assembly of an improved neat appearance.

In the arrangement of FIGS. 12 and 13, the stent is intended for use inthe mitral position, but is constructed without the metal ring 50 aroundits periphery. Instead, a cloth ring is provided, which serves a similarpurpose, providing a means for attachment to the heart. The stent 63shown in FIG. 12 is similar to the stent 32 in that it is provided witha comparable grouping of apexes and support arms, and larger and heavierthan the stents for use in the aortic position. Thus, there are apexes64, 65 and 66 interconnected by downwardly scalloped upper arms 67, 68and 69 beneath which are lower arms 70, 71 and 72. Extending around thebottom periphery of the stent is a cloth ring 73. This is ofdoubled-over construction, with the lower arms 70, 71 and 72 receivedinside it. The outer edge, where the attachment is made to complete thedouble-walled cloth construction, is inwardly folded, as seen in FIG.13. At the locations of the posts 75, 76 and 77, where the lower armsare connected to the upper portion of the stent, it is necessary to omitthe outer layer of the cloth ring 73, as shown in FIG. 12.

It is to be remembered that the heart has four primary valves: two ofwhich carry the blood away from the heart, the aortic and pulmonaryvalves; and two atrioventricular valves, the mitral and tricuspidvalves. Since the aortic and pulmonary valves are similar inconfiguration as are the mitral and tricuspid valves, and since thedevice referred to herein as an aortic valve stent is equally suited tothe pulmonary location, it is to be understood that the terms aortic andmitral are descriptive of the type of application and are notrestrictive to a particular anatomic location.

The present invention also comprehends a device in which the spacingsbetween the various apical portions are all unequal (each space beingdifferent from each other space). Using one space as the reference thesecond is approximately 4-10% less than said reference (space), and thethird space is 17% to 33% less than said reference (space).

It is to be understood that cloth may be used to cover the frame in anyone of a number of configurations. The cloth may be a seamless cylinder,or flat stock cut, formed and seamed, or specially preformed material.The methods described previously in this specification are by way ofspecific illustration.

I claim:
 1. A stent for .[.a.]. .Iadd.an animal .Iaddend.heart valve.Iadd.for supporting such a heart valve in its natural contour.Iaddend.comprising a framework of annular configuration,said frameworkincluding .[.spaced.]. .Iadd.three rounded .Iaddend.apical portions.Iadd.at one end thereof, said apical portions being rounded convexly asviewed from said one end and being spaced apart unequal angulardistances, .Iaddend.and arms interconnecting said apicalportions,.Iadd.each of said apical portions having a substantialcircumferential dimension for permitting said apical portions toaccommodate heart valves of different dimensions, .Iaddend.for therebyproviding an attachment for the commissures and cusps of a heart valve,said arms being in two sets .Iadd.spaced apart axially.Iaddend.,one ofsaid sets being adjacent said apical portions and the other of said setsbeing remote from said apical portions.[...]..Iadd., all of said arms inat least the one of said sets adjacent said apical portions being curvedin a scalloped configuration so as to incline away from said apicalportions intermediate said apical portions, for conforming to the shapeof and supporting the margins of the cusps of an animal heart valve suchthat the peripheral parts of said heart valve can be attached to saidarms while preserving the natural contour of said heart valve,said armsof said set remote from said apical portions being more nearly flat thanare said arms of said set adjacent said apical portions. .Iaddend.
 2. Adevice as recited in claim 1 in which said arms in both of said setsincline axially away from said apical portions intermediate said apicalportions. .[.3. A device as recited in claim 2 in which at least some ofsaid arms are deflectable for varying the distances thereof from theaxis of said framework..].
 4. A device as recited in claim 2 in whichsaid sets of said arms .[.are spaced apart axially and.]. are generallyequally spaced from the axis of said framework,thereby providing saidset of said arms adjacent said apical portions and said set of said armsremote from said apical portions.
 5. A device as recited in claim 4including, in addition, a cloth member extending over and receiving saidarms.
 6. A device as recited in claim 4 including, in addition, a clothring attached to and extending outwardly from said remote set of saidarms for providing a means for attachment to a heart. .[.7. A device asrecited in claim 4 including in additiona ring circumscribing saidframework adjacent said remote set of arms, and including meansprojecting radially outwardly from said framework for securing said ringthereto..]. .[.8. A device as recited in claim 4 in which said arms insaid one set are deflectable toward said apical portions for therebyincreasing the radial spacing of said adjacent arms from the axis ofsaid framework..]. .[.9. A device as recited in claim 4 in which saidarms are curved in a scalloped configuration to so incline away fromsaid apical portions intermediate said apical portions, said arms insaid one set being deflectable and having a greater inclination awayfrom said apical portions than that of said arms in said other set,forproviding a relatively large increase in the spacing of said arms insaid one set from the longitudinal axis of said framework upondeflection of said arms in said one set toward said apical portions..].10. A device as recited in claim 1 including in addition a ring attachedto said framework for providing a means for attachment of said frameworkin a heart in the mitral position, said ring circumscribing saidframework adjacent said arms. .[.11. A device as recited in claim 10 inwhich said ring is a rigid member integral with said framework..].
 12. Adevice as recited in claim 10 in which said ring is a cloth membersecured to said arms. .[.13. A device as recited in claim 1 in whicheach of said apical portions is rounded and has a substantialcircumferential dimension for permitting said apical portions toaccommodate heart valves of different dimensions..]. .[.14. A device asrecited in claim 1 in whichsaid arms are arcuate and concave on thesides thereof adjacent said apical portions,said arms in said one setbeing bendable toward said apical portions for thereby increasing theirspacing from the axis of said framework..].
 15. A device as recited inclaim 1 in which the spacing between two adjacent apical portions isless than the spacing between either of said two adjacent apicalportions and the third of said apical portions.
 16. A device as recitedin claim 15 in which said spacing between said two adjacent apicalportions is within the range of 17% to 33% less than said spacingbetween either of said two adjacent apical portions and the third ofsaid apical portions.
 17. A device as recited in claim 15 in which saidspacing between said two adjacent apical portions is within the range of20% to 25% less than said spacing between either of said two adjacentapical portions and the third of said apical portions. .[.18. A deviceas recited in claim 1 in which said framework is an integral member ofsubstantially noncorrosive metal..]. .[.19. A device as recited in claim18 in which said metal is malleable..]. .[.20. A device as recited inclaim 1 in which said framework is an integral member of plasticmaterial..].
 21. The invention as claimed in claim 1 in which there arethree apical portions spaced unequal angular distances from each other,one space between two adjacent apical portions being a reference space,another space between two adjacent apical portions being 4-10% less thansaid reference space, another space between two adjacent apical portionsbeing 17-33% less than said reference space. .[.22. A heart valveassembly comprising a stent,said stent including a generally tubularframework having spaced apexes at one end, a first seet of arms adjacentand interconnecting said apexes, and a second set of arms spaced fromsaid first set of arms and remote from said apexes,said arms beinginclined away from said apexes at locations intermediate said apexes, aheart valve on said framework,said heart valve having commissuressubstantially at said apexes and cusps having marginal portions adjacentsaid arms, the marginal portions of said heart valve overlapping saidframework so that the interior of said framework is covered by saidmarginal portions of said heart valve, and means for attaching saidheart valve to said framework..].
 23. A device as recited in claim.[.22.]. .Iadd.37 .Iaddend.in which said marginal portions of said heartvalve are doubled over said framework. .[.24. A device as recited inclaim 22 in which said heart valve includes a free marginal edgeextending from said one end for providing a means for attachment to aheart..]. .[.25. A device as recited in claim 22 including in addition aring of clothlike or spongelike material circumscribing said frameworkinwardly of said one end of said framework..].
 26. A device as recitedin claim .[.22.]. .Iadd.37 .Iaddend.including in addition a sleeve.Iadd.of cloth material .Iaddend.receiving said arms, portions of saidheart valve extending over said sleeve. .[.27. A device as recited inclaim 26 in which said sleeve is of cloth material..]. .[.28. A heartvalve assembly for use in the mitral position comprisinga stent,saidstent including a generally tubular framework having spaced apexes atone end and arms interconnecting said apexes,said arms being inclinedaway from said apexes at locations intermediate said apexes, a ringextending outwardly of said arms adjacent the opposite end of saidframework, an annular member circumscribing said arms, means attachingsaid annular member to said framework, a heart valve on saidframework,said heart valve having cusps having marginal portionsoverlapping said framework, means attaching said marginal portions tosaid framework,said heart valve having additional portions extendingover the end of said ring remote from said apexes and toward saidannular member, and means attaching said additional portion of saidheart valve to said annular member..]. .[.29. A device as recited inclaim 28 in which said annular member is constructed of felt..]. .[.30.A device as recited in claim 28 including in addition a layer of clothover said overlapping marginal portions for covering the same andproviding for fibrous ingrowth upon being grafted in a heart..]. .[.31.A device as recited in claim 28 in which said ring is integral with saidframework..]. .[.32. A device as recited in claim 28 in which said ringis a cloth member attached to said arms..]. .[.33. A stent for a heartvalve comprising a framework of annular configuration,said frameworkincluding spaced apical portions and arms interconnecting said apicalportions,for thereby providing an attachment for the commissures andcusps of a heart valve, a ring attached to said framework for providinga means for attachment of said framework in a heart in the mitralposition,said ring circumscribing said framework adjacent said arms, andan annular member interposed between said ring and said framework forproviding a bed for the attachment of portions of the valve extendedover the atrial aspect of said ring, and for providing a hemodynamicseal upon grafting in a heart..]. .[.34. A device as recited in claim 33in which said annular member is constructed of felt..].
 35. A stent for.[.a.]. .Iadd.an animal .Iaddend.heart valve .Iadd.for supporting such aheart valve in its natural contour .Iaddend.comprisinga framework ofannular configuration,said framework including .Iadd.three.Iaddend.spaced apical portions .Iadd.at one end thereof .Iaddend.andarms interconnecting said apical portions,for thereby providing anattachment for the commissures and cusps of a heart valve, .Iadd.saidarms being in two sets spaced apart axially, one of said sets beingadjacent said apical portions and the other of said sets being remotefrom said apical portions, said arms in at least the one of said setsadjacent said apical portions being curved in a scalloped configurationso as to incline away from said apical portions intermediate said apicalportions for conforming to the shape of and supporting the margins ofthe cusps of an animal heart valve such that the peripheral parts ofsaid heart valve can be attached to said arms while preserving thenatural contour of said heart valve, .Iaddend. each of said apicalportions being rounded .Iadd.convexly as viewed from said one end,.Iaddend.and having a substantial circumferential dimension forpermitting said apical portions to accommodate heart valves of differentdimensions, said apical portions being annular and of generally ovalshape. .[.36. A stent for a heart valve comprisinga framework of annularconfiguration,said framework including spaced apical portions, armsinterconnecting said apical portions, for thereby providing anattachment for the commissures and cusps of a heart valve, said armsinclining away from said apical portions intermediate said apicalportions, said arms including a set of at least two of said armsintermediate each adjacent pair of apical portions,said arms in each setbeing spaced apart axially and generally equally spaced from the axis ofsaid framework, thereby providing arms adjacent said apical portions andarms remote from said apical portions, a ring circumscribing saidframework adjacent said remote arms, and a relatively short postextending axially away from said apical portions at the junctures ofsaid remote arms,said posts including portions bent outwardly to providea radially projecting means for securing said ring to said framework..]..Iadd.37. A heart valve assembly comprisinga stent, said stentincludinga generally tubular framework having three apexes at one endthereof,said apexes being rounded convexly as viewed from said one endand being spaced apart unequal angular distances, each of said apexeshaving a substantial circumferential dimension, a first set of armsadjacent and interconnecting said apexes, and a second set of armsspaced from said first set of arms and remote from said apexes,all ofsaid arms of at least said first set being arcuate so as to incline awayfrom said apexes at locations intermediate said apexes, an animal heartvalve on said framework,said heart valve having commissuressubstantially at said apexes and cusps having marginal portionssubstantially conforming to said arms of said first set, the marginalportions of said heart valve overlapping said framework so that theinterior of said framework is covered by said marginal portions of saidheart valve, sutures attaching said heart valve to said framework sothat said commissures are secured to said apexes and said marginalportions of said cusps are secured to said arms, and said heart valve issupported in substantially its natural contour with all its peripheralparts securely attached to said framework, and a ring of clothlike orspongelike material circumscribing said framework inwardly of said oneend of said framework for conforming to and providing a hemodynamic sealat the aortic root of a heart upon implantation. .Iaddend.